ungrounding brushes?


XS400 New Member
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hey guy i have a 1977 xs 400 does any one know it you have to unground the brushes on the xs 400 for the simple striped down wiring, cuz on the xs650 you do?, im only running the kick strat and not much else, and if any one knows why you have to unground them. and how to get to them thanks.

i can get the bike to run with just the rec but when i add the reg i have a guronding problem and im getting continuity on the brush leads so that must mean that there bonded together.

has any one eles ran in to this or know that to do? thanks.
What brushes? There is an alternator that has 3 white wires to the rectifier and a field coil with normally a black and a green wire (green to the regulator). The starter motor has brushes but nothing else I think?
there is continuity on the the green and black wire leads on stator, so that must mean that there bonded together/grounded. there for a you have a short. how can charge the system if you have a short that will kill the BAT?
there are on nicks in the wire and every thing is tight
does any one know what to do or look for?
There should be continuity between the green and black wires for the coil to work as it is basically one long wire with a voltage running through it. Do you mean there is a short between the wires before it reaches the field coil so the coil is not exciting? Where are you testing the coil? You can test it by taking off the round alternator cover but you will lose some oil.
In a nutshell, you should be testing resistance not continuity

field winding should be about 4 ohms green/green or green/black

3 white wires to stator each one in sucession .72 ohms

variations will occur proportionate to the temperature
my ohms reading for green and black is in the range 5 to 4 ohms.
what should the resistance be on the spark plug coils?
im geting a spark on the right side coil when i take the leads off, but not the left side.
i checked power to ground and it reads good up to the coil but then i plug it in i get a spark.
the resistance/continuity reads the same between the two my be i have a bad coil?
im not sure how to tell
what exactly is your problem? alternator is nothing to do with the plugs/coils.

your getting me confused now

have we answered your first question?
The XS650 only needs to unground the brushes if you put an 80 up reg/rec onto a 70-79 bike. It has nothing to due with running just a kick start or simplfied wiring. I have not spent much time studying the XS400 but I assume the systems are simular.
On your 77 does it have separate regulator and recifier?
I'll check a parts fiche and see what it looks like.
In the parts fiche it shows a stator and a feild coil with a rotor tjhat spins between them. No brushes.
It does have a separate reg and rec. The way it looks you can replace the separate units for the combo unit with out too much trouble. I'll look at a wiring diagram and get back with you.
From looking at the diagrams it looks like a pretty much a straight up swap to convert from the older mechanical reg and rec to the later combo reg/rec. Or due the Chrysler/ Radio Shack conversion.
Research them on 650.com.